Can it use up to several gigabytes if you overdo it a bit?
Of course, you do not have to overdo it. Pretty much any movie in usable picture / sound quality will probably already have> 1GB.
I bet all your superfluous questions here have already consumed more.
More than 1 GB
What does "> 1 GB" mean in your world?
With high picture quality you can count about 3GB per hour.